Certain 1, 2-diazetidines and their preparation



United States Patent 3,129,215 CERTAIN 1,2-DIAZETIDINES AND THEIRPREPARATION David Horvitz, Cheverly, Mi, assignor, by mesne assignments,to FMC Corporation, New York, N.Y., a corporation of Delaware NoDrawing. Filed May 14, 1958, Ser. No. 735,099 12 Claims. (Cl. 260-439)This invention relates to a new class of organic chemical compounds anda method for producing the same. More particularly, the compounds of theinvention are alkyl substituted diazetidines derived from dialkylsubstituted hydrazines.

The compounds of this invention are 1,2-alkyl diazetidines asrepresented by the following structural formula:

wherein R is a lower alkyl group having from 1 to 4 carbon atoms, and Rand R", which may be either the same or different, are hydrogen or analkyl group having from 1 to 4 carbon atoms. The Rs also may be the sameor different. The preferred compound of the invention is1,2-dimethyl-diazetidine, having the following structural formula:

These new compounds are useful as rocket fuels or rocket fuel additives.Particularly outstanding in this respect are 1,2-dimethyldiazetidine and1,2-diethyldiazetidine. Their usefulness for this purpose is due to thepeculiar structure of the compounds. They are highly endothermic becauseof the nitrogen to nitrogen bonds and the strained four-membered ring.Consequently, a high specific impulse is obtained when these compoundsare used with any of the oxidizers commonly employed in rocketpropulsion such as nitric acid, oxygen, etc. It has also been determinedthat these compounds are hypergolic with white fuming nitric acid and,therefore, offer further advantages as rocket fuels. The low freezingpoints of these compounds, e.g. 91.6 to --88.8 C. for1,2-dimethyldiazetidine, is another important factor in determiningtheir suitability for such uses.

In accordance with the present invention, it has been found that1,2-dialkyldiazetidines may be prepared from the reaction betweendialkyl substituted hydrazines and organic dihalides. The reaction maybe operated at room temperature, though reaction rates and yields areincreased by utilizing higher temperatures up to a maximum of about 150C. The preferred temperature range is, however, about 50 to 100 C.

The 1,2-dialkyl substituted hydrazines useful for the present purposeswill correspond to the following structural formula:

RHN-NHR wherein the Rs are alkyl groups having from about 1 to 4,preferably about 1 to 2, carbon atoms. The Rs may be the same ordifferent. Examples of both straight chain 3,129,215 Patented Apr. 14,1964 ice and branch chain dialkyl substituted hydrazines which can beutilized include:

ROH-CHR" wherein R and R" are either hydrogen or alkyl groups havingfrom about 1 to 4 carbon atoms while the halogen substituents areindicated by X. It will also be understood that R and R" may either bethe same or different. The halogen substituents may be chlorides,bromides, and iodides. In accordance with the preferred features of theinvention, the chlorides and bromides are preferred, since the use ofiodides results in the formation of undesirable polymeric material.Specific examples of dihalides useful in this process include:

Ethylene dichloride Ethylene dibromide 1,2-dichloro-3-methylpropane1,2-propylene dibromide 1,2-butylene dichloride 2,3-butylene dibromide1,2-hexylene dibromide, etc.

In general, it is preferred to carry out the reaction between theorganic dihalide and the dialkyl substituted hydrazine in an inertreaction medium. Conventional reaction media may be employed, thoughsuch organic compounds as aromatic hydrocarbons, aliphatic hydrocarbons,aralkyl hydrocarbon, cycloalkanes, ethers, alcohols, etc. have beenfound to be particularly useful. Specific examples of operable reactionmedia include pentane, hexane, cyclohexane, benzene, toluene,naphthalene, diethyl ether, dibutyl ether, ethyl alcohol, butyl alcoholand the like. The reaction medium serves to dissolve the reactants andto prevent undesirable polymerization side reactions from taking place.The ratio of the reaction medium to reactants may be within the range ofabout 5:1 to 50:1, preferably about 10 parts of the solvent to 1 part ofthe reactants.

In order to neutralize the acidic by-products of the reactions takingplace in the process, it is desirable to have an alkaline reagentpresent in the reaction mixture. A stoichiometric excess of the dialkylsubstituted hydrazines may be employed for this purpose, though such usetends to increase side reactions. It has also been found that strongbases such as sodium hydroxide and potassium hydroxide are alsounsuitable, since they dehalogenate the organic dihalide reactantthereby reducing the yield and increasing the quantities of undesirableby-products. The use of mild alkaline reagents is, therefore, preferred.Such reagents are, for example, the alkali metal and alkaline earthmetal carbonates. Illustrative compounds are sodium carbonate, potassiumcarbonate, calcium carbonate, barium carbonate, etc. The amount ofalkaline reagent employed may vary over a wide range, though only thatamount sufiicient to substantially neutralize the acid by-products needbe employed.

In accordance with another feature of the invention, it has been foundessential to control carefully the relative proportions of reactantsemployed. The highest yields are obtained when utilizing substantiallystoichiometric amounts of the organic dihalide and the dialkylsubstituted hydrazine. As previously noted, the use of an excess of thehydrazine derivative results in the formation of certain polymerizationproducts. More specifically, when the mol ratio of the alkyl substitutedhydrazine to the organic dihalide' becomes appreciably greater than onewith a high concentration of reactants in solution, the yield of thediazetidine derivatives becomes quite small and the major product is acompound corresponding to the following structural formula:

wherein R, R and R are as previously defined. It will be understood thatsuch compounds will usually be formed in minor proportions even whencarrying out the reaction under the most favorable conditions for theproduction of the diazetidine derivatives. If the preparation of a majoramount of hydrazinotype compounds is desired, the useof excessdisubstituted'hydrazine reactants will be employed; These compounds arealso novel and, similarly to the diazetidine compounds, they may be usedas a rocket propellant in conjunction with the common oxidizers listedabove.

The invention will be more fully understood by reference tothefollowin'g specific embodiment.

Example A solution of 30 parts of symmetrical dimethylhydrazine and 135parts of sodium carbonate in 290 parts of xylene was heated to 100 C.with mechanical agitation. To this mixture was added a solution of 94parts of ethylene dibromide in 90 parts of xylene. The resultingreaction mixture was distiiled, and the recovered distillate separatedinto two layers. The top layer formed the bulk of the distillate, whilethe bottom layer amounted to only about 15 parts.

The top layer was fractionally distilled and 1,2- dimethyldiazetidinerecovered therefrom. The molecular weight of the dimethyld-iazet-idineso recovered was 89 (theoretical value is 86.14) as determined byfreezing point depression in benzene. A test with methylmagnesium iodideshowed the absence of any active hydrogen. This test confirmed thestructure of the compound as being:

CH3N'N-CH3 HgCCHz and eliminated the possibility of the compound being1- methyl-l-vinyl-Q-methyl hydrazine:

oH NHN-H CH=OH1 LZ-dimethyldiazeticline is a colorless liquid boiling at70.2-70.4" 0/7 60 mm. It freezes at 9l.6 to 8'8.8 C. The density wasdetermined to be 0.8099 gm./liter at 25 C., and the index of refractionwas n =1.4130. Molecular refraction was determined as 26.52 as comparedto the calculated value of 26.40. Elementary analysis for carbon,hydrogen and nitrogen gave the following figures:

4 The bottom layer contained 1,2-bis-(N,N'-dimethylhydrazino) ethane:

The novel compound, 1,2-dimethy1diazetidine, may also be employed toform plastic materials by polymerination with conventional acidcatalysts. Thus, linear polymers of the form (N-N-CHzOHzN-NCH2OH) 1 CH3CH3 CH5 CH3 are produced. The higher, dialkyl diazetidines are alsouseful in the preparation of polymers. It is possible, therefore,toobtain a variety of new polymers from the novel diazetidine compounds ofthis invention. The novel 1,2-bis-( N,N' dialkylhydrazine)alkylene compounds may be also employed as monomers in the preparationof novelnitrogen-containing polymers.

While a particular embodiment of this invention is shown above, itwillbe understood that the invention is obvious subject to variousmodifications without departing from its broader aspects.

What is claimed is:

1. A compound having the formula:

RHJJ-C'EHR" wherein R is a lower alkyl radical, and R and R" areselected from the group consisting of hydrogen and a lower alkylradical.

2. The compound of claim 1 wherein R is an alkyl radical having from 1to 4 carbon atoms.

3. The compound of claim 1 wherein R and R" are hydrogen.

4. 1,2-dimethyldiazetidine.

5. A process which comprises reacting a lower dialkyl substitutedhydrazine and-a lower. alkyl vicinal dihalide in a mol'ratio of saiddialk-yl substituted hydrazine to said alkyl dihalide of about 1 to 1 inthe presence of an inert reaction medium and a mild alkaline reagentother than said' dialkyl substituted hydrazine at a temperaturerangingfrom room temperature up to about 150 C. to produce, a reactionmixture containing at least one chemical compound having the formula:

R'HCCHR" wherein. R is a lower alkyl radical and R and R are selectedfrom the group consisting of hydrogen and a lower alkyl radical.

6. The process of claim 5 wherein said alkyl substituted hydrazine hasthe structural formula:

wherein R is an alkyl group having from 1 to 4 carbon atoms.

7-. The process of claim 5 wherein said alkyl halide has the structuralformula:

wherein R and R" are selected from the groupconsis-ting of hydrogen anda lower alkyl halide, and X is a halide.

8. The process of claim 7 wherein R and R are hydrogen.

9. The process of claim 7 wherein X is bromide.

10. The process of claim 5 wherein said reaction temperature is withinthe range of about 50 to C.

5 6 11. A process which comprises heating about stoioho- -12. Theprocess of claim 11 wherein said alkaline remetnic amounts ofdimethylhydrazine and ethylene diagent is sodium carbonate. bromide at atemperature within the range of about 50 References Cited in the file ofthis patent to 150 C. in the presence of an inert organic reaetionmedium and an alkaline reagent selected from the group 5 UNITED A ES PAENTS consisting of alkali metal and alkaline earth metal carbo- 2 4 5 5D yf J l 20, 1948 nates to obtain a. reaction mixture containing 1,2-di-2 55 17 Cramer Dem 14, 1948 methyldiazeti'dine, and separating saidLZ-dimethyldi- 2 643 250 s n 1 23 1953 azetidine therefrom 2,802,031Horvitz Aug, 6, 1957 10

1. A COMPOUND HAVING THE FORMULA:
 5. A PROCESS WHICH COMPRISES REACTINGA LOWER DIALKYL SUBSTITUTED HYDRAZINE AND AL OWER ALKYL VICINAL DIHALIDEIN A MOL RATIO OF SAID DIALKYL SUBSTITUTED HYDRAZINE TO SAID ALKYLDIHALIDE OF ABOUT 1 TO 1 IN THE PRESENCE OF AN INERT REACTION MEDIUM ANDA MILD ALKALINE REAGENT OTHER THAN SAID DIALKYL SUBSTITUTED HYDROZINE ATA TEMPERATURE RANGING FROM ROOM TEMPERATURE UP TO ABOUT 150*C. TOPRODUCE A REACTION MIXTURE CONTAINING AT LEAST ONE CHEMICAL COMPOUNDHAVING THE FORMULA: